Over the past decade there have been tremendous advances in biomedical imaging technology. For example, magnetic resonance imaging, X-ray computed tomography, ultrasound, and confocal microscopy are all in widespread research and clinical use, and have resulted in fundamental and dramatic improvements in health care. However, there are many situations where existing biomedical diagnostics are not adequate. This is particularly true where high resolution (.about.1 .mu.m) imaging is required. Resolution at this level often requires biopsy and histopathologic examination. While such examinations are among the most powerful medical diagnostic techniques, they are invasive and can be time consuming and costly. Furthermore, in many situations conventional excisional biopsy is not possible. Coronary artery disease, a leading cause of morbidity and mortality, is one important example of a disease where conventional diagnostic excisional biopsy can not be performed. There are many other examples where biopsy can not be performed or conventional imaging techniques lack the sensitivity and resolution for definitive diagnosis.
Moreover, for medical procedures such as balloon angioplasty, conventional techniques have not been able to provide high resolution imaging of the artery while a balloon is being inflated. Many other interventional procedures would greatly benefit from high resolution, in-vivo visualization technology. This technology would be useful for performing preoperative and post-operative diagnostics, to alert medical personnel to problems, or to avoid problems encountered during medical procedures.
The present invention seeks to overcome the problems associated with such conventional imaging techniques.